Associated model not getting linked with custom finder method

DeliveriesController.php

<?php
// In my controller:
$delivery = $this->Deliveries->get($id, [
  'contain' => ['Warehouses', 'DeliveryNotes', 'Orders', 'Products' => function ($q) {
    return $q->find('filtered', ['options' => ['group' => 'ean']])
      ->select(['Products.id', 'ProductInfo.sku', 'ProductInfo.id', 'Products.size', 'Products.product_info_id'])
      ->contain('ProductInfo');
  }]
]);

note.txt

Delivery model is populated, but associated products[] is empty. Running the generated SQL in a console returns the data perfectly.

output.sql

// Generated SQL:
SELECT 
  Deliveries.id AS `Deliveries__id`, 
  ...
SELECT 
  (
    COUNT(Products.id)
  ) AS `pcs`, 
  (
    COUNT(Products.reservation_id)
  ) AS `reserved`, 
  Products.id AS `Products__id`, 
  ProductInfo.sku AS `ProductInfo__sku`, 
  Products.size AS `Products__size` 
FROM 
  products Products 
  INNER JOIN product_info ProductInfo ON ProductInfo.id = (Products.product_info_id) 
WHERE 
  Products.delivery_id in (69) 
GROUP BY 
  Products.product_info_id, 
  Products.size

ProductsTable.php

<?php
// Custom finder method in Table
public function findFiltered(Query $query, array $options)
{
  if (!empty($options['options']['group'])) {
    switch ($options['options']['group']) {
      case 'ean':
        $query
          ->group(['Products.product_info_id', 'Products.size'])
          ->select(['pcs' => $query->func()->count('Products.id')])
          ->select(['reserved' => $query->func()->count('Products.reservation_id')]);
        break;
    }
  }
  return $query;
}